From patchwork Wed May 8 14:43:22 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "kirill.shutemov@linux.intel.com" X-Patchwork-Id: 10936047 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 447D2924 for ; Wed, 8 May 2019 14:52:45 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 363D827FA8 for ; Wed, 8 May 2019 14:52:45 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2A7FB286CD; Wed, 8 May 2019 14:52:45 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BB25527FA8 for ; Wed, 8 May 2019 14:52:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727812AbfEHOoe (ORCPT ); Wed, 8 May 2019 10:44:34 -0400 Received: from mga04.intel.com ([192.55.52.120]:61857 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727315AbfEHOoe (ORCPT ); Wed, 8 May 2019 10:44:34 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga104.fm.intel.com with ESMTP; 08 May 2019 07:44:33 -0700 X-ExtLoop1: 1 Received: from black.fi.intel.com ([10.237.72.28]) by fmsmga008.fm.intel.com with ESMTP; 08 May 2019 07:44:29 -0700 Received: by black.fi.intel.com (Postfix, from userid 1000) id 9AE752E5; Wed, 8 May 2019 17:44:28 +0300 (EEST) From: "Kirill A. Shutemov" To: Andrew Morton , x86@kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Borislav Petkov , Peter Zijlstra , Andy Lutomirski , David Howells Cc: Kees Cook , Dave Hansen , Kai Huang , Jacob Pan , Alison Schofield , linux-mm@kvack.org, kvm@vger.kernel.org, keyrings@vger.kernel.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: [PATCH, RFC 02/62] mm: Add helpers to setup zero page mappings Date: Wed, 8 May 2019 17:43:22 +0300 Message-Id: <20190508144422.13171-3-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190508144422.13171-1-kirill.shutemov@linux.intel.com> References: <20190508144422.13171-1-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP When kernel setups an encrypted page mapping, encryption KeyID is derived from a VMA. KeyID is going to be part of vma->vm_page_prot and it will be propagated transparently to page table entry on mk_pte(). But there is an exception: zero page is never encrypted and its mapping must use KeyID-0, regardless VMA's KeyID. Introduce helpers that create a page table entry for zero page. The generic implementation will be overridden by architecture-specific code that takes care about using correct KeyID. Signed-off-by: Kirill A. Shutemov --- fs/dax.c | 3 +-- include/asm-generic/pgtable.h | 8 ++++++++ mm/huge_memory.c | 6 ++---- mm/memory.c | 3 +-- mm/userfaultfd.c | 3 +-- 5 files changed, 13 insertions(+), 10 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index e5e54da1715f..6d609bff53b9 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -1441,8 +1441,7 @@ static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf, pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); mm_inc_nr_ptes(vma->vm_mm); } - pmd_entry = mk_pmd(zero_page, vmf->vma->vm_page_prot); - pmd_entry = pmd_mkhuge(pmd_entry); + pmd_entry = mk_zero_pmd(zero_page, vmf->vma->vm_page_prot); set_pmd_at(vmf->vma->vm_mm, pmd_addr, vmf->pmd, pmd_entry); spin_unlock(ptl); trace_dax_pmd_load_hole(inode, vmf, zero_page, *entry); diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h index fa782fba51ee..cde8b81f6f2b 100644 --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h @@ -879,8 +879,16 @@ static inline unsigned long my_zero_pfn(unsigned long addr) } #endif +#ifndef mk_zero_pte +#define mk_zero_pte(addr, prot) pte_mkspecial(pfn_pte(my_zero_pfn(addr), prot)) +#endif + #ifdef CONFIG_MMU +#ifndef mk_zero_pmd +#define mk_zero_pmd(zero_page, prot) pmd_mkhuge(mk_pmd(zero_page, prot)) +#endif + #ifndef CONFIG_TRANSPARENT_HUGEPAGE static inline int pmd_trans_huge(pmd_t pmd) { diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 165ea46bf149..26c3503824ba 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -675,8 +675,7 @@ static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, pmd_t entry; if (!pmd_none(*pmd)) return false; - entry = mk_pmd(zero_page, vma->vm_page_prot); - entry = pmd_mkhuge(entry); + entry = mk_zero_pmd(zero_page, vma->vm_page_prot); if (pgtable) pgtable_trans_huge_deposit(mm, pmd, pgtable); set_pmd_at(mm, haddr, pmd, entry); @@ -2101,8 +2100,7 @@ static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { pte_t *pte, entry; - entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); - entry = pte_mkspecial(entry); + entry = mk_zero_pte(haddr, vma->vm_page_prot); pte = pte_offset_map(&_pmd, haddr); VM_BUG_ON(!pte_none(*pte)); set_pte_at(mm, haddr, pte, entry); diff --git a/mm/memory.c b/mm/memory.c index ab650c21bccd..c5e0c87a12b7 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2927,8 +2927,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf) /* Use the zero-page for reads */ if (!(vmf->flags & FAULT_FLAG_WRITE) && !mm_forbids_zeropage(vma->vm_mm)) { - entry = pte_mkspecial(pfn_pte(my_zero_pfn(vmf->address), - vma->vm_page_prot)); + entry = mk_zero_pte(vmf->address, vma->vm_page_prot); vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, &vmf->ptl); if (!pte_none(*vmf->pte)) diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index d59b5a73dfb3..ac1ce3866036 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -122,8 +122,7 @@ static int mfill_zeropage_pte(struct mm_struct *dst_mm, pgoff_t offset, max_off; struct inode *inode; - _dst_pte = pte_mkspecial(pfn_pte(my_zero_pfn(dst_addr), - dst_vma->vm_page_prot)); + _dst_pte = mk_zero_pte(dst_addr, dst_vma->vm_page_prot); dst_pte = pte_offset_map_lock(dst_mm, dst_pmd, dst_addr, &ptl); if (dst_vma->vm_file) { /* the shmem MAP_PRIVATE case requires checking the i_size */